Sample rate conversion is essential in most signal processing applications. The need for sample rate conversion may arise due to various reasons, including, as examples: (a) designs with an Analog to Digital converter (ADC) rate different from a receive base-band symbol rate in digital communication systems; (b) variable bandwidth receive systems with a fixed analog-to-digital convertor (ADC) rate; and (c) designs with a digital-to-analog convertor (DAC) rate different from a transmit baseband sampling rate. Typical resampling approaches include Lagrange and B-Spline resampling to match the sampling rates.
Many signal processing applications specify an estimate of the value of the sampled signal at particular time instants other than during the sampling instances. This is accomplished using digital sample rate convertors often referred to as resamplers. Resamplers may be broadly classified into fixed rate resamplers and variable rate resamplers. As shown in FIG. 1, fixed rate resamplers such as resampler 100 convert the input signal from a fixed input rate to a fixed output rate. With variable rate resamplers, either the input rate or the output rate or both are variable. The input and output rates of resampler 100 are related by a resampling ratio which may be defined as the ratio of output rate to input rate, r=fo/fi. Fixed rate conversion by simple integer ratios are well understood and may be implemented using poly-phase structure and fixed coefficients. The need for resamplers may arise in both transmitter and receiver signal processing chains. There are heretofore unaddressed needs with previous variable rate resampling solutions.